9am: Today on the London mayoral live blog we will be discussing the environment and green policies in London, with special guests Jenny Jones, the Green candidate for mayor of London, Simon Birkett, an air quality expert from Clean Air in London, and Murad Qureshi, the Labour chair of the London assembly environment committee.

Post your questions for each of them below.

The focus today will be on the environment, but if elected Jones will have to deal with all the various issues that come across the mayor's desk – so please feel free to ask her about any policy or political matters, from policing to housing to the Olympics and more.

She is chair of the planning and housing committee, a member of the police and crime committee – she has campaigned against kettling – and a member of the transport committee. She lists her key issues on the assembly website as:• Housing costs and condition

A tireless campaigner, Jones is an immensely likeable character who loves to stir things up in City Hall. This slightly eccentric, but extremely passionate, former archaeologist has a love/hate relationship with the mayor. Never backing down from a fight, she will be a wildcard in the mayoral election and will seek to unsettle her more well-known opponents.

I have this mental image of these two huge dinosaurs battling it out – Ken and Boris – and it's going to be very difficult to get between them because they are such powerful personalities, such powerful forces. But I see the Green candidate as this little mammal that is actually the future. You know there little voles or rats or something coming through the middle and representing the future, and that's how I see the Green party.

She has stood twice for parliament in London constituencies, coming fourth both times.

Policies

The skyline of the City of London. Photograph: Paul Owen Paul Owen/Guardian

On the City, she calls for the replacement of the Corporation of London with a more conventionally democratic borough, with its funds used for jobs and affordable homes, the creation of an investment bond to raise money for the Greater London Authority and Transport for London, and support for small and medium-sized businesses, local community banks, and building societies. Under Jones, the GLA would "try to ensure" it only used the services of and took sponsorship money from banks that were lending to small businesses.

Jones promises to build at least 15,000 "genuinely affordable" homes per year, refurbish over a million properties to cut energy bills, "reform" the private rental sector to bring down rents, and introduce an "ethical lettings agency".

Jones also promises to work with employers to create thousands of training places, apprenticeships and jobs.

She suggests new roads and river crossings should only be for public transport, cycling and walking, and cyclists and pedestrians should have priority at traffic lights, and wants a 20mph limit on residential streets, plus faster and safer cycle paths, the layout of dangerous junctions changed, and the cycle hire scheme expanded.

She also calls for a "very low emission zone" in central London and wants to make all buses "low emission hybrids or better" by 2016. And she wants teams to go door to door helping people "make their homes warmer with lower bills and lower carbon emissions".

The Greens are probably the only party standing in the mayoral election to put out a two-page policy document entitled "Animals are important". It calls for London's governing bodies to buy cleaning products that are not tested on animals and campaign against animal testing, promote the consumption of less meat, and introduce tougher licensing conditions for pet shops.

Environment

But Boris Johnson's record as mayor has been criticised by environmental campaigners. Johnson, a former climate change sceptic, scrapped the western extension to the congestion charge, got rid of Ken Livingstone's proposed £25 congestion charge for the most polluting cars, and delayed for 15 months the third phase of the capital's low emission zone, which covers the most polluting vans. He has also been criticised for not issuing smog alerts when London's air quality has been at its worst and for delaying and fudging measures to improve it. The capital's air quality has long been below EU standards (the government predicts it will be within EU limits for one measure of air quality for 2011, although it is breaching another measure by a factor of two) and it hit record levels of pollution on Thursday 15 March this year. A report commissioned by Johnson estimated that 4,300 people a year die prematurely due to pollution, mostly from exhaust pipes. The mayor has also been criticised for slow progress in encouraging electric vehicle use, introducing few diesel-electric hybrid buses and for improving the greenness of little of the existing bus fleet. He has also proposed a new airport to the east of London, nicknamed "Boris Island", something the government is now to consult on.

On the other side of the ledger, Johnson opposes a third runway at Heathrow, which he says would be "an environmental disaster". It "will not be built while I am mayor", Johnson has pledged. His nine-point plan for London includes restoring green space and planting 20,000 trees, as well as continuing to expand and improve the public transport network – his most visible improvements so far have been to the "Overground" local train lines, which by the end of this year will link up in the south as an "orbital" route – and the cycle hire scheme, which Livingstone proposed but Johnson introduced. He is committed to cutting London's carbon emissions by 60% by 2025, a pledge his predecessor also made.

Ken Livingstone's policies were more positively received by green groups – particularly his most dramatic move, the congestion charge, although a study led by Professor Frank Kelly of King's College London last year found that there was little evidence the charge had improved air quality. Transport for London says that now congestion is back to pre-charge levels but would have been "much worse" without the charge. Livingstone in office was seen as being a particularly keen promoter of public transport – the bus network especially was improved during his eight years in power, and the Oyster card system was introduced to speed up journey times and encourage public transport use – and he counted the Green party as allies during his time as mayor, with Jones being his deputy mayor from 2003-04, as mentioned above. He says he will not bring back the western extension to the congestion charge but will revisit his proposed £25 charge for polluting cars. However, his plan to build a Thames Gateway road bridge has always been unpopular with green campaigners.

Brian Paddick, the Liberal Democrat candidate, has promised to make London carbon-neutral by 2030 through promoting energy-efficiency and new technologies, "kick-start a recycling revolution" and revise the air quality strategy. He also wants to encourage household insulation, increase the number of electric vehicles, and introduce a "clean air zone" in central London deterring the oldest, most polluting vehicles. He also proposes planting an extra 2m trees by 2025.

Interestingly, he is no longer proposed to revisit his old idea for a £25-a-day "gas guzzler" charge on the most polluting cars. He says now this would be too expensive.

The transport document also concentrates on his 7% fare cut policy, and how he would pay for it. A February 2012 Transport for London board paper highlighted by Livingstone yesterday (see page one, paragraph two) showed a total £338m surplus in Transport for London's operating budget. Livingstone puts the cost of his fare cut at £270m.

He confirms that he would not bring back the western extension of the congestion charge abolished by Boris Johnson, saying that would be too expensive too, and would not reinstate drinking on public transport.

He says he would leave Boris's eight new Routemaster buses in place but would not buy any more, putting the cost at £2m each (Johnson says future Routemasters will only cost the same as a hybrid bus).

He says he would review the cycle hire contract with Barclays, which he has called "the cheapest sponsorship deal ever" and would require sponsors to make a plan to make the cycle hire scheme more attractive to a wider range of Londoners. He would try to roll it out to south London.

Staying with cycling, he would review major junctions, trial a cyclists-only green traffic light phase, redesign the cycle superhighways, expand the "Greenways" cycle routes, extend the freedom pass to allow older people to use the cycle hire scheme for free, and work with boroughs for consistent cycle lanes across the capital.

He says he would return the age of eligibility of the freedom pass to age 60, promises better bus services in the suburbs, and says he will "get a grip" on tube delays, freeze the congestion charge for the full four years of his term, and "build the case" for Crossrail 2, the South London line to Victoria, the Cross-River Tram from Camden across Waterloo Bridge to Peckham and Brixton, and extensions to the Docklands Light Railway and Croydon tram.

He would make a third of all tube stations accessible to those who can't use steps by 2016, start a campaign for more courtesy on public transport, including trialling "keep your feet off" designs on buses, introduce a system to allow drivers to get information on their phones about where the nearest parking spaces are, campaign for rickshaws to be banned, and link up pedestrianised spaces in central London so people can walk in a pleasant environment from Bank to Oxford Street.

Livingstone would also campaign against the proposed route of High Speed 2, and for a route "that doesn't demolish hundreds of London homes". And "if it is not too late by May" he would negotiate with the International Olympic Committee to ensure the maximum possible access for black cabs to the Olympic Route Network.

Livingstone says he will announce plans to cut air pollution separately at a later date.

12.50pm:Jenny Jones is here now to answer your questions. Murad Qureshi of the London Assembly environment committee and Simon Birkett of Clean Air in London have already started responding.

12.54pm:Jenny Jones has started by answering my question about how she will use the mayor's powers to get the 15,000 affordable homes built that she plans to.

Boris Johnson secured a £1.7bn budget up to 2015, which was a 66% cut compared to the last affordable housing budget. We'd use this and the large amount of land owned by the GLA to build as many homes as possible, keeping rents at a genuinely affordable level. Boris is happy for rents to go up to 80% of market rates, making more people even more dependent on housing benefits. We would also work closely with councils, housing associations and co-operatives to be much more bullish in using compulsory purchase powers, other publicly owned land and public money to build homes. The problem we all face is that land is so expensive in London, it's what underpins the astronomical house prices, so we would also campaign for a Land Value Tax to bring down the cost of building and buying homes.

1.00pm: I also asked Jenny Jones if Ken Livingstone had agreed to make her his deputy mayor if he wins the election, given she had asked her supporters to give Livingstone their second preference votes. She replied:

No but he will make me Supreme Commander of walking and cycling, and has promised a big budget and a free reign to make TfL sort out the safety problems so even children and grannies like me feel happy walking and cycling around London.

Top of the list is a massive campaign to build public understanding of the dangers of air pollution with advice for people on protecting themselves (aka adaptation) and reducing pollution for themselves and others (aka mitigation).

The former includes walking or cycling down side streets if possible rather than down a red route behind a bus. The latter includes walking or cycling, if we can; if not, then trying to use public transport; and avoiding driving around in diesel vehicles unless necessary. Also, of course, don't light bonfires on smoggy days!

Boris says he wants to warn people but it's not true - if it was he'd have issued smog alerts.

The public understanding campaign needs to be on the scale of those for smoking, alcoholism or obesity as health risks of a similar scale.

I just want to reiterate about the second vote for Ken. It would be very hard for me to advocate such a move. Only if JJ was to become deputy with Ken that a number two will even enter onto my ballot. But saying that what is your main reason for Ken as our number two?

The Green party didn't suggest giving Ken a second preference just so we could get jobs from him. We're saying that because if I don't get through to the second round and it's a play off between him and Boris Johnson, we want Ken because we can work with him and get measures enacted to make London fairer and greener.

Hi Jenny, increasingly police cars can be seen in London's parks harassing and threatening cyclists with fines, criminal records etc. At the same time, irresponsible driving on roads surrounding the parks is visibly on the up and police is nowhere to be seen. Can we demand cyclists dismount in parks unless the roads are made safe for them? What is your view on this?

There does seem to be some confusion about who causes the biggest disruption to our transport system. I think that it's motorised vehicles that cause congestion, pollution and community upheaval. Cyclists are generally making things better for us all, plus staying healthy themselves. Having said that, I was knocked off my bike by someone cycling through a red light, so I don't support illegal moves like that.

You're right, we must make our roads safe so that there is absolutely no excuse not to be on them. I would prefer parks to be cycle friendly, with cyclists being responsible (ie not going too fast) and courteous to people walking.

The next mayor will have a whole raft of new housing powers. Following the news yesterday that rents in inner London rose three times faster than wages last year, what would you do to ease the pressure on those struggling with their housing costs. And how could you make the private rented sector more stable for families?

First, we would build at least 15,000 homes at a genuinely affordable level - see my previous answer for details. I would also continue to campaign for radical reforms to the private rented sector. It's crazy that a quarter of households are stuck in a sector that only offers six months of stability and such high rents. At the heart of our proposals is a default five year tenancy, so tenants could move at two months' notice but landlords couldn't kick tenants out or put the rent up for those five years. We also need to reform the tax system so it is worthwhile for landlords, tackle mortgage lenders who force landlords to offer these terrible fixed 12 month tenancies, and take out rogue landlords. As a practical step I want to set-up an Ethical Lettings Agency for London, which the Green party in Brighton is working on already.

Aerial view of London and the river Thames. Photograph: Graeme Robertson

1.19pm:Murad Qureshi answered my question about which environmental policies his Labour colleague Ken Livingstone ought to be pursuing but isn't:

l would like to see Ken put more emphasis on water issues amongst his environmental policies. With a drought coming this summer, an incoming mayor will have to be on top of water issues like reducing our demand for water as well as increasing supplies in the future. Also we need to make better use of our waterways – that's the Thames, canals and rivers – for example in transporting passengers and freight. In the latter instance it would help relieve the numbers of lorries on our roads when we have major infrastructural works like Crossrail.

Hi Jenny - I am inclined to vote Green by nature, but recently most of the policies I have seen from the party have essentially been very standard left/socialist policies around minimum wages and opposing the cuts and so on.

Can you describe three or four really good environmental ideas that you would like the GP to champion in the assembly, or implement if it wins? How will encourage the deployment of green technologies and encourage environmentally friendly businesses in the capital?

- Boost green spaces – set up a support team in City Hall to complete the All London Green Grid, which was a Green party initiative, and to work with boroughs to map and implement local opportunities to enhance green and blue infrastructure eg wildlife corridors, trees, natural flood plains.

- Put pedestrians and cyclists first in road design especially at major junctions, applying the Dutch-style design for cycle lanes, and introduce a pay-as-you-drive replacement for the congestion charge to reduce traffic so our streets are less congested and polluted.

- Build a new generation of small and smart waste facilities so that we can become self-sufficient in waste processing and recycle at least 70% of our waste by 2030.

- Cut GLA group's building energy usage by 10% in first year of office, upgrade all building to be A rated by 2016 and become a zero carbon public service by 2020.

Do check our website after 14 April, when all our policies will be there.

Safety for all vulnerable road users is high on my agenda. Every road death costs the taxpayer well over a million pounds, so can be argued from a financial perspective, as well as being a tragic waste of a life, impacting on families and society. I work with RoadPeace, a charity that works with road casualty victims and their families. The unfairness, the injustice of people being hurt on the roads, is a big motivator for me.

We can:

- Adopt Dutch road design principles for Cycle superhighways and the london cycle network to provide clear, dedicated and safe space for cyclists on main roads.

There are almost too many big differences to be able to choose just one, but ...

Greens want a sustainable city that can withstand the problems of climate change. We're already seeing food and energy prices rise - if we don't make plans for more local supplies then life will become a struggle for us all.

Making the environment a priority is good for the economy, and certainly good for anyone a lower income. It's a win win situation if we insulate houses - lower bills, lower carbon emissions, or if we grow more of our own food - fresher and cheaper, lower carbon emissions.

I wasn't very keen on the system that Labour proposed. It gave power to the mayor without enough checks and balances. However, London has definitely benefited from an elected mayor; we need somebody thinking about the whole region, ensuring our transport system works seamlessly, for example. We actually think the mayor should have power over other areas so that we could make sure everyone has a similar, decent recycling and food waste system, and so we can protect pan-London homelessness services. But we think it's a mistake to put so much power and a £15bn budget in the hands of one individual, so we would prefer to see the mayor draw a cabinet from the London Assembly, and to give the assembly much more power over budgets and strategies so they can really hold the mayor to account.

It will be interesting to see the impact in other places.

A Cornish pasty. Photograph: Alamy

1.39pm:Jenny Jones has answered the key political question of the week: when and where did you last eat a pasty?

No he hasn't promised me deputy mayor and I wouldn't want it. I did it before and it was a bit ceremonial for me. I prefer to be more political.

Whilst Ken is far from perfect, we know could work with him to ensure as much of our policy agenda as possible would be taken forward. (This isn't possible with Boris Johnson, or other senior Labour politicians!) From 2004-2008 we worked with him to set-up the London Living Wage Unit, start the All London Green Grid which has restored hundreds of acres of green space, and triple the cycling budget.

a) You're often clashing with black cab drivers on Twitter. Surely if you're going to drive down vehicle emissions, you should be working with the cab industry to get it more fuel efficient, instead of battling against it?

b) Do you regret questioning the amount of money being spent on the phone hacking investigation?

Yes, I will work with them. Interestingly, I'm getting more friendly with cabbies now that Boris has let them down.

As mayor I would do (at least) three things for cabbies – two would give them opportunities to be greener, the other would improve their working life:

1) Scrap the turning circle requirement

2) Create a fund to help them clean up their vehicles, either by replacement or by retrofitting

3) Clamp down in a huge way on illegal minicabs

Do you regret questioning the amount of money being spent on the phone hacking investigation?

No. It's easy to be wise after the event, but based on the information the Met were giving us, the case wasn't going any further. As a member of the Met police authority, it was my job to question their use of resources. Although it's a huge budget, it's had massive cuts. They don't spend enough on rape cases - should that have priority over privacy issues?

I believe that public transport should be cheaper than driving a car. I would bring down fares by increasing the congestion charge for vehicles - £15 for ordinary, £40 for gas guzzlers (hope you are reading Simon's answers on air pollution). I would also research 'pay as you drive' for London. Successive governments, while in opposition, have promised to bring this in, but lose courage once elected. It's the only way we can keep down fares in the long term, as well as demonstrating the true cost of motoring, ie congestion, pollution, community disruption and road casualties.

I can't recall the Green party making a noise about the shockingly high number of cycle deaths in London. Indeed the comments I recall from you on transport show a remarkably supine attitude (and we're not talking recumbent) to the issues faced by me and my comrade green transport advocates.

Cycling in London should be as pleasant an experience as in the very best provision provided by other cities. After all, all I hear from politicians is we will provide this 'world class' thingummy or that 'world class' oojiflip. Empty words I fear, but you want us to take positive action, by going out to vote, when inaction is in evidence from City Hall.

We are different - we make all our decisions collectively, by debate and then voting. So for example, our London manifesto was endlessly critiqued by any London member who wanted to read and respond. Changes were debated and wording agreed.

We're also exceptionally supportive of women; of our five 'senior elected' people, three are women.

Until recently we didn't have a leader, just Principal Speakers on lots of topics, but we decided it was a way of getting our message out more widely. However, our leader has the same status as a brand new member - just the one vote.

2.03pm: Jenny Jones has responded to criticisms of her comments about the dog that attacked police officers in east London. She said soon afterwards: "Calling in CO19 just seems such an expensive way to deal with a mad dog. Could they not have used a Taser? Police should have done their homework before carrying out that operation. They should have realised the potential for a dangerous dog at the premises." She said the raid appeared to be "an expensive mistake".

Given your recent, err ... eccentric Twitter comments regarding the cost of policing (the ones where you bemoaned the cost of police equipment used to subdue a dog which severely injured three police officers) do you intend to implement this as policy: putting cost before the lives and wellbeing of London's police officers?

They are, after all, voters and people too. Many of them will have been quite disturbed by your Twitter comments. To many it will seem that your interest in their wellbeing is somewhat minimal.

Of course the police are an easy target for bashing and doing so is cheap and easy publicity for a politician such as yourself.

How can London's police officers have confidence that your leadership will not further erode their ability to protect London?

Hello, I've copied your email in full, just so those who haven't already written to me complaining about my statements know what you mean.

It wasn't Twittering, it was about a quote given to a journalist. He didn't know all the facts, so couldn't tell me, but the raid sounded like a messed up operation, not a disastrous and damaging incident. If I had known that officers had been hurt, I'd not have given the same quote, although I was right about their not having enough intelligence, which was negligent and put those officers in unnecessary danger.

I have been called by New Scotland Yard. I gave an apology, which they are going to pass on.

But your last question is crucial. I have had a prickly relationship with the Met over the past 12 years - if you sit on a body that has to agree to staggering sums of compensation to the people the Met gets it wrong with, then you despair at their ability to damage their own reputation.

However, the new commissioner has implemented some of the things I was most keen to change over the years: he is reducing stop and search (SO bad for community relations and with a 6% success rate) and he is cracking down on illegal drivers. I most certainly can work with him.

I've also called for a moratorium on cuts to the police budget. It needs trimming hard in many areas (HMIC says 12% efficiency savings from over time and surveillance budget), but not as fast or as indiscriminately as this government has done.

That was all Jones had time for, unfortunately. Thanks very much for her for answering so many questions, and thanks to you for posting so many good ones.

I'll sum up the key points from her answers shortly.

2.14pm: Incidentally Ken Livingstone has weighed in to the "pasty tax" issue. He's in favour of pasties and pies and against the new tax (which adds VAT to hot food sold by bakeries and supermarkets). Livingstone said:

Like most Londoners I can't understand why the Tories want to introduce a new tax on pies - putting 20% on the cost of pasties and sausage rolls.

London is famous around the world for pie and mash. We have some fantastic pie and mash shops in London from Romford to Shepherd's Bush - I believe we have the best pies in the world.

Thousands of Londoners work in the catering industry - why do the Tories want threaten their jobs? If Boris Johnson won't stand up for London on this issue I will.

Livingstone's press team were keen for the media to know that recently Ken had visited F Cooke's in Harold Hill, "a range of Greggs stores" and Cooke's Pie and Mash shop.

Today he ate a pasty in Hammersmith (left).

2.40pm:Jenny Jones, the Green party candidate, was online at lunchtime answering your questions. Here are the key points:

•Jones defended herself against criticism of her comments about the dog that attacked police officers in east London. Soon after the incident she said: "Calling in CO19 just seems such an expensive way to deal with a mad dog. Could they not have used a Taser?" Today she told Guardian readers she had not known that officers had been hurt when she spoke out, but she stood by her point that they had not had enough intelligence about whether a dangerous dog was there, "which was negligent and put those officers in unnecessary danger". She said she had apologised to Scotland Yard.

•She said she agreed with recently-appointed Metropolitan police commissioner Bernard Hogan-Howe's decision to change aspects of stop and search and crack down on illegal vehicles, and said "I most certainly can work with him".She attacked the pace of cuts to the Met police budget.

•She said that despite calling on her voters to give Ken Livingstone their second-preference vote, he had not promised to make her deputy mayor again and she wouldn't want to do it anyway. "I did it before and it was a bit ceremonial for me. I prefer to be more political." She explained why she had made the second-preference call: "We're saying that because if I don't get through to the second round and it's a play off between him and Boris Johnson, we want Ken because we can work with him and get measures enacted to make London fairer and greener."